Expansion drilling bit



Sept. 22, 1931. E. s. HARTSON 1,324,268 I EXPANSION DRILLING BIT Filed July 30, 1928 JWVEA/ To flTro/ZA/EK Patented Sept. 22, 1931 EARL S. HA'RTSON, OF LOS ANGELES, CALIFORNIA EXPANSION DRILLING BIT Application filed July 30,

My invention relates to an expansion drilling bit that is designed for use in the drilling of deep wells, and the principal objects of my invention are to generally improve upon 5 and simplify the construction of the existing forms of expansion drilling bits, and toprovide a bit that is relatively simple in construction, inexpensive of manufacture, of strong and durable structure, and positive in action.

Further objects of my invention are to con struct the drilling bits and to connect the same to each other and to the head or body of the drill so that said bits will be positively expanded by a downward movement of the head or body relative to said bits and likewise said bits will be drawn toward each other by an upward movement of the head or body relative to the bits.

lVith the foregoing and other objects in view, my invention consists in certain novel features of construction and arrangement of parts that will hereinafter be more fully described and claimed and illustrated in the accompanying drawings, in which Fig. 1 is a vertical section taken through the center of a drilling bit of the fish-tail type and which embodies the principles of my invention.

0 Fig. 2 is a vertical section taken on the line 22 of Fig. 1.

Fig. 3 is a sectional View of the lower portion of the bit and showing the same in expanded position.

Fig. 4 is a horizontal section taken on the line -il4 of Fig. 1.

Fig. 5 is a horizontal section taken on the line 5-5 of Fig. 1.

Fig. 6 is a vertical section taken through the lower portion of a diamond point drilling bit that is constructed in accordance with my invention.

Referring by numerals to the accompanying drawings, 10 designates a substantially cylindrical member that forms the body of the expansion drill and formed integral with the upper end thereof is an externally threaded pin 11 that is adapted to be screw seated in the lower end of a drill pipe or coupling member 12.

1928. Serial N0.'296,310.

The lower portion of the drill body 10 is provided with a diametrically arranged slot 13 for the accommodation of the expanding bits or cutters and formed through the upper portion of the body 10 and the pin 11 is an axially disposed circulation duct 14.- having branches 15 that lie to the exterior of the body 10, perferably at points slightly above the upper end of the slot 13.

Arranged for vertical sliding movement in the slot 13 are the upper portions of a pair of identical bits or cutters 16 having pointed lower ends 17 that are curved slightly outward. The upper inner portions of the bits or cutters 16 are reduced in thickness so as to provide overlapping portions 18, the thickness of which is equal to the thickness of the outer lower portions of the cutters and extending through the upper portions of these overlapping parts is a pin 19 that pivotally connects the bits or cutters to each other. The length of the pivot pin 19 is such that its ends bear against the side faces of the slot 13 when the cutters are properly positioned therein.

Formed through the bodies of the bits or cutters 16 are slots 20 that are curved or illclined toward the axis of the tool, and passing through these slots are pins 21, the ends of which are seated in the body 10 to the sides of the slot.

Under normal conditions, or while the bit is not in service, for instance while it is being raised or lowered through the well hole, the weight of the bits causes the same to occupy a position in the lower portion of slot 18, as illustrated in Figs. 1 and 2, and when so positioned the pins 21 occupy the upper ends of the slots 20.

hen it is desired to expand the bits or cutters to enlarge the drill hole, for instance during underreaming operations, the drill pipe 20 carrying the body 10, is lowered a short distance so that the pins 21 are moved downwardlv through the curved or inclined slots 20 and as a result of the pin and slot engage ment between the body 10 and bits or cutters the latter will move to the upper end of slot 13 and simultaneously said bits or cutters will swing upon the pivot pin 19 so. that the lower portions of said bits or cutters will swing outwardly away from each other into eX- panded position, as illustrated in Fig. 3, and rotation of the tool will now cause the outwardly projecting portions of the cutters to engage the surrounding formation and cut or drill an enlarged hole therein.

In Fig. 6 I have illustrated a diamond point drill embodying the principles of my invention, and where such construction is employed the bits or cutters 2-2 which have overlapping pointed lower ends are pivotally connected by a pin or bolt 23 and formed through the upper outer portions of the cutters are curved or in clined slots 24 through which pass pins 25 that are seated in the body of the tool.

lVhere this form of drill is used and the body is moved downward relative to the bits or cutter, the latter will swing on the pivot pin 23 and as a result of the pin and slot connections between the upper portions of the cutters and the body of the tool, said upper portions will move upwardly and outwardly to form a cutting tool of increased diameter.

In some instances it may be found desirable to reverse the arrangement of the pin and slot connections between the cutters and the body of the tool and this is accomplished by forming inclined or curved slots in the side faces of the slot 13, and which slots receive pins or lugs that project outwardly from the upper portions of the bits or cutters.

Thus it will be seen that I have provided an expansion drilling bit that is relatively simple in construction, inexpensive of manufacture, positive in action, and very effective in performing the functions for which it'is intended.

It will be understood that minor changes in the size, form and construction of the various parts of my improved expansion drilling bit may be made and substituted for those herein shown and described without departing from the spirit of my invention the scope of which is set forth in the appended claims.

I claim as my invention:

1. In an expansion drilling bit, a body provided in its lower portion with a centrally arrangedslot, a pair of bits arranged within said slot so as to move vertically therein, the upper inner corners of the bodies of which bits overlap each other, a pivot pin passing through the overlapping upper inner corners of said bi s, the bodies of the bits below and outwardly from the point of pivotal connection being provided with arcuate slots and pins seated in the body near the lower end thereof, which pins pass through said arcuate slots.

2. In an expansion drilling bit, a body provided in its lower portion with a centrally arranged slot, the bottom of which is pro vided with a pair of oppositely arranged inclined faces that diverge from thetransverse center of said slot, a pair of bits arranged within said slot and adapted to move vertically therein, the upper ends of which bits are provided with straight fiat faces disposed at right angles to the straight outer edges of said bits, which straight flat faces are adapted to engage the inclined bottom faces of the slot when said bits are elongated and expanded, the upper inner corners of which bits overlap each other, a pivot pin seated in the overlapping upper inner corners of said bits, oppositely arranged arcuate slots formed through the bodies of the bits below and outside the pivotal connection between said bits and pins seated in the lower portion of the drill body and passing through said slots.

In testimony whereof I affix my signature.

EARL S. HARTSON. 

